Characterization of UHMWPE/wood composites produced via dry-blending and compression molding

2013 ◽  
Vol 34 (4) ◽  
pp. 510-516 ◽  
Author(s):  
A. Mahfoudh ◽  
A. Cloutier ◽  
D. Rodrigue
Keyword(s):  
Compression Molding ◽  
Wood Composites

Comparison of Novel Conductive Open- and Closed-Porous PPy-PLA Composites

2009 ◽  
Author(s):  
Christine Chan ◽  
Ellen Chan ◽  
Weijia Zhang ◽  
Hani E. Naguib
Keyword(s):  
Relative Density ◽  
In Situ Polymerization ◽  
Compression Molding ◽  
Salt Leaching ◽  
Conductive Composites ◽  
Order Of Magnitude ◽  
Density Values ◽  
Average Size ◽  
Porous Composites

This study compared the fabrication techniques and characterization of novel open- and closed-porous structures in PPy-PLA conductive composites. For the open-porous composites, PLA samples were fabricated using compression molding and salt leaching with varying salt-to-polymer mass ratios, which were subsequently coated with PPy by in situ polymerization of pyrrole and iron (III) chloride. For the closed-porous composites, a patterned structure of PPy within PLA was created using compression molding of PPy-coated PLA pellets, followed by gas saturation and foaming techniques in order to create the closed pores. Characterization of both porous composites included their physical, mechanical, and electrical properties. Results showed that the modulus increased with increasing relative density and decreasing open porosity. The open-porous composites had lower relative density values but higher open porosities compared to the closed-porous composites. The average size of the closed pores was approximately an order of magnitude larger than the open pores. Lastly, the open-porous composites had higher conductivity values than the closed-porous composites due to the greater surface area of the continuous conductive pathway. The comparisons between open- and closed-porous composites established their characteristic properties for their future development in applications.

scholarly journals Manufacturing and Characterization of Highly Environmentally Friendly Sandwich Composites from Polylactide Cores and Flax-Polylactide Faces

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 342
Author(s):  
Diego Lascano ◽  
Rene Guillen-Pineda ◽  
Luis Quiles-Carrillo ◽  
Juan Ivorra-Martínez ◽  
Rafael Balart ◽  
...  
Keyword(s):  
Sandwich Structures ◽  
Great Influence ◽  
Weight Ratio ◽  
Environmentally Friendly ◽  
Compression Molding ◽  
Hot Compression ◽  
Honeycomb Core ◽  
The Core ◽  
Core Thickness

This work focuses on the manufacturing and characterization of highly environmentally friendly lightweight sandwich structures based on polylactide (PLA) honeycomb cores and PLA-flax fabric laminate skins or facings. PLA honeycombs were manufactured using PLA sheets with different thicknesses ranging from 50 to 500 μm. The PLA sheets were shaped into semi-hexagonal profiles by hot-compression molding. After this stage, the different semi-hexagonal sheets were bonded together to give hexagonal panels. The skins were manufactured by hot-compression molding by stacking two Biotex flax/PLA fabrics with 40 wt% PLA fibers. The combined use of temperature (200 °C), pressure, and time (2 min) allowed PLA fibers to melt, flow, and fully embed the flax fabrics, thus leading to thin composite laminates to be used as skins. Sandwich structures were finally obtained by bonding the PLA honeycomb core with the PLA-flax skins using an epoxy adhesive. A thin PLA nonwoven was previously attached to the external hexagonal PLA core, to promote mechanical interlock between the core and the skins. The influence of the honeycomb core thickness on the final flexural and compression properties was analyzed. The obtained results indicate that the core thickness has a great influence on the flexural properties, which increases with core thickness; nevertheless, as expected, the bonding between the PLA honeycomb core and the skins is critical. Excellent results have been obtained with 10 and 20 mm thickness honeycombs with a core shear of about 0.60 and facing bending stresses of 31–33 MPa, which can be considered as candidates for technical applications. The ultimate load to the sample weight ratio reached values of 141.5 N·g−1 for composites with 20 mm thick PLA honeycombs, which is comparable to other technical composite sandwich structures. The bonding between the core and the skins is critical as poor adhesion does not allow load transfer and, while the procedure showed in this research gives interesting results, new developments are necessary to obtain standard properties on sandwich structures.

scholarly journals Preparation and Characterization of Cellulose Nanofibril Films from Wood Fibre and Their Thermoplastic Polycarbonate Composites

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
S. Panthapulakkal ◽  
M. Sain
Keyword(s):  
Thermal Properties ◽  
Tensile Modulus ◽  
Compression Molding ◽  
Strength Properties ◽  
Diameter Distribution ◽  
Cellulose Nanofibril ◽  
Molding Process ◽  
Pulp Fibres ◽  
High Temperature Tensile

The aim of this study was to develop cellulose-nanofibril-film-reinforced polycarbonate composites by compression molding. Nano fibres were prepared from wood pulp fibres by mechanical defibrillation, and diameter distribution of the fibres produced was in the range of 1–100 nm. Nanofibre films were prepared from the nanofibre suspensions and were characterized in terms of strength properties, crystallinity, and thermal properties. Strength and modulus of the nano fibre films prepared were 240 MPa and 11 GPa, respectively. Thermal properties of the sheets demonstrated the suitability of processing fibre sheets at high temperature. Tensile properties of the films subjected to composite-processing conditions demonstrated the thermal stability of the fibre films during the compression molding process. Nanocomposites of different fibre loads were prepared by press-molding nano fibre sheets with different thickness in between polycarbonate sheet at 205°C under pressure. The tensile modulus and strength of the polycarbonate increased with the incorporation of the fibres. The strength of the thermoplastic increased 24% with 10% of the fibres and is increased up to 30% with 18% of the fibres. Tensile modulus of the polycarbonate demonstrated significant enhancement (about 100%).

Development and Characterization of Novel Conductive Polypyrrole-Polylactide Open-Porous Composites

2009 ◽  
Author(s):  
Christine Chan ◽  
Weijia Zhang ◽  
Hani E. Naguib
Keyword(s):  
In Situ Polymerization ◽  
Compression Molding ◽  
Mass Ratio ◽  
Uncoated Sample ◽  
Salt Leaching ◽  
Mechanical And Electrical Properties ◽  
Mass Ratios ◽  
Porous Composites

Novel polypyrrole-polylactide blends were fabricated and characterized using compression molding, salt leaching, and in situ polymerization. Open-porous polylactide samples were fabricated using compression molding and salt leaching techniques with varying salt-to-polymer mass ratios of 3:1, 6:1, and 9:1. The samples then underwent in situ polymerization of pyrrole and iron (III) chloride to obtain a uniform coating of polypyrrole. Characterization of these novel composites comprised of their physical, mechanical, and electrical properties. With increasing salt-to-polymer mass ratio, it was found that the relative density decreased, the open porosity increased while pore size and pore density generally remained independent. The polypyrrole coating did not have a significant effect on the structure of the pore network. Microscopic polypyrrole nodules were observed to be uniformly coated on the surface and sub-surface of the composites. The compressive modulus decreased with increasing salt-to-polymer mass ratios. In addition, the modulus of the coated 3:1 salt-to-polymer mass ratio sample was twice the value obtained for the uncoated sample while the modulus values for the 6:1 and 9:1 samples did not significantly change. The conductivity increased as the salt-to-polymer mass ratio increased. The relationships observed between the structure and resulting properties provided the basis for future development and characterization of these novel porous composites.

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